Safety and feasibility of mapping and stem cell delivery in the presence of an implanted left ventricular assist device: a preclinical investigation in sheep.

The objective of this study was to determine the safety and feasibility of performing transendocardial electromechanical mapping and mesenchymal precursor stem cell injections after left ventricular assist device (LVAD) implantation in a sheep model of acute myocardial infarction. Six sheep were assigned to either an acute or chronic group. Then we created an acute myocardial infarction in each by occluding the distal left anterior descending coronary artery with a balloon for 90 minutes. All the sheep underwent LVAD implantation 30 days later. On the same day, sheep in the acute group underwent transendocardial cell injections and were euthanized. Sheep in the chronic group received cell injections 2 weeks after LVAD implantation and were euthanized 30 days later. The presence of the LVAD or the use of chest-closure wires did not interfere with electromechanical mapping. Furthermore, no adverse events were observed during electromechanical mapping or the stem cell injections. In all sheep, the LVAD flow rate was approximately 4 L/min during mapping and the injections, and no adjustments were required. Histologic analysis confirmed that the mesenchymal precursor stem cells were successfully delivered. No differences were observed between the acute and chronic groups. In conclusion, our study showed that transendocardial electromechanical mapping and stem cell injections are safe and feasible in the presence of an LVAD. Surgically implanted metal devices, including the LVAD, steel chest-closure wire, and skin staples, were compatible with the electromechanical mapping system.